emerge --update --newuse --deep --with-bdeps=y @world --exclude python:2.7

Calculating dependencies /

!!! Problem resolving dependencies for net-wireless/python-wifi from @selected                                                                                                                                                             ... done!

!!! The ebuild selected to satisfy "net-wireless/python-wifi" has unmet requirements.
- net-wireless/python-wifi-0.5.0-r3::net-kit USE="-examples" PYTHON_TARGETS="-python2_7"

  The following REQUIRED_USE flag constraints are unsatisfied:
    python_targets_python2_7

  The above constraints are a subset of the following complete expression:
    any-of ( python_targets_python2_7 )

(dependency required by "@selected" [set])
(dependency required by "@world" [argument])